How to Increase Metabolism After 40 (What Actually Works)

You can improve your energy expenditure, maintain or build muscle, and support your metabolic health after 40. But you probably don’t need to fix a metabolism that suddenly slowed down because of your age.

Research suggests that metabolism, after accounting for differences in body size and composition, remains relatively stable throughout much of adulthood.

So why does maintaining your weight sometimes feel more difficult in your 40s than it did in your 20s?

Your daily routine may have changed. You might spend more time sitting, have less time for exercise, sleep poorly, or have experienced changes in muscle mass and body composition.

Hormonal transitions and certain medical conditions can also influence weight management.

The good news is that many of these factors can be addressed.

You don’t need expensive metabolism supplements, punishing workouts, or extreme diets. Here’s what the evidence actually supports and how to build a practical routine after 40.

Does Your Metabolism Really Slow Down After 40?

Not in the dramatic way popular diet advice often suggests.

A major study published in Science in 2021 examined daily energy expenditure across a large and diverse population, from infancy through older adulthood.

Researchers found that energy expenditure, after adjusting for body size and fat-free mass, remained relatively stable between approximately ages 20 and 60.

A more pronounced age-related decline appeared later in adulthood.

That challenges the idea that turning 40 causes a sudden metabolic slowdown.

Your metabolism doesn’t automatically fall off a cliff when you reach middle age.

However, there’s an important distinction between metabolism adjusted for body composition and the total number of calories you actually burn.

Someone who loses muscle, becomes less active, or loses substantial body weight may have lower daily energy requirements even if their underlying metabolic processes haven’t changed dramatically with age.

What Makes Up Your Daily Calorie Burn?

Your body uses energy in several ways.

Component	What it means	Can you influence it?
Resting metabolism	Energy used for essential bodily functions	Partly, through body composition and health
Exercise activity	Energy used during intentional workouts	Yes, through activity choice and duration
Everyday movement	Walking, household chores, standing, and other movement	Yes, by changing daily routines
Thermic effect of food	Energy used to digest, absorb, and process food	Modestly, through food composition and intake

Together, these contribute to total daily energy expenditure, commonly called TDEE.

Understanding the distinction matters because many supposed metabolism boosters have very small effects on resting calorie expenditure.

By contrast, increasing regular physical activity can meaningfully change your total daily energy use.

If you’d like to understand how these measurements differ, our guide to BMR vs. TDEE explains the two concepts.

Why Weight Management Can Become Harder in Your 40s

Even without a sudden metabolic slowdown, several changes can make weight management more challenging.

You May Be Moving Less

Think about how your routine has changed over the past decade.

Maybe you previously walked to work, played recreational sports, or spent more time moving throughout the day.

Now you might work at a desk, commute by car, and spend evenings sitting.

These changes can reduce energy expenditure without being particularly noticeable.

You might still eat similar meals even though your activity level has changed.

Over time, that difference can influence body weight.

Muscle Mass and Strength Can Change

Muscle mass and strength tend to decline with aging, particularly during later adulthood and with prolonged inactivity.

But the rate varies substantially, and age-related muscle loss isn’t inevitable at a fixed pace for everyone.

Resistance training can help preserve and improve muscle mass and strength well beyond age 40.

That matters for physical function, independence, and body composition.

However, building a few pounds of muscle won’t automatically increase resting calorie expenditure by hundreds of calories per day.

The metabolic effect is more modest than fitness marketing often suggests.

Hormonal Changes May Affect Body Composition

For women, perimenopause and menopause can involve changes in estrogen levels, sleep, symptoms, and fat distribution.

Fat may become more concentrated around the abdomen even without a dramatic increase in total body weight.

The Menopause Society identifies menopause-related hormonal changes as an important contributor to increasing abdominal fat during midlife.

But menopause doesn’t mean weight gain is unavoidable or that metabolism suddenly stops working.

For men, testosterone levels may change with age, although the timing and degree of decline vary.

Low testosterone can affect body composition and other aspects of health, but ordinary weight gain doesn’t establish a testosterone deficiency.

These differences are reasons to take an individualized approach, not to assume that everyone over 40 needs hormone treatment.

1. Strength Train to Maintain Muscle and Improve Body Composition

If you’re going to prioritize one form of structured exercise after 40, resistance training deserves serious consideration.

It can help preserve muscle during weight loss, improve strength, support bone health, and make everyday activities easier.

A 2025 systematic review and meta-analysis involving 53 trials and 2,873 middle-aged and older adults found that combining aerobic and resistance training supported reductions in body fat while also benefiting lean body mass.

Importantly, the research supports combining different forms of activity rather than assuming that lifting weights makes cardio unnecessary.

How Often Should You Lift Weights?

Current CDC recommendations include muscle-strengthening activity on at least two days per week, involving all major muscle groups.

You can train more often if you’re comfortable, recovering well, and interested in doing so.

But three or four gym sessions aren’t mandatory.

A simple two-day routine can be an effective starting point.

Movement	Beginner-friendly exercise	Suggested starting approach
Squat	Chair squat or bodyweight squat	1–2 sets of 8–12 repetitions
Hip hinge	Glute bridge or light dumbbell deadlift	1–2 sets of 8–12 repetitions
Push	Wall push-up or dumbbell chest press	1–2 sets of 8–12 repetitions
Pull	Resistance-band row	1–2 sets of 8–12 repetitions
Core	Bird dog or modified plank	1–2 comfortable sets

Choose resistance that allows you to maintain control and good technique.

As exercises become easier, gradually increase repetitions, resistance, or sets.

You don’t need to exhaust yourself or reach muscle failure in every workout.

If you’ve been inactive or have joint, heart, or other medical concerns, ask a qualified professional about appropriate modifications.

Our guide to building a home workout routine can help you get started without a gym membership.

2. Eat Enough Protein, but Don’t Overdo It

Protein helps support muscle maintenance and repair, particularly when combined with resistance training.

It can also contribute to fullness, which may make weight management easier.

However, your protein requirements don’t automatically double when you turn 40.

The appropriate amount depends on factors such as body size, training, health conditions, and whether you’re losing weight.

How Much Protein Do You Need After 40?

For many healthy adults who exercise regularly, approximately 1.2–1.6 grams of protein per kilogram of body weight daily can be a useful planning range.

It’s not a universal requirement.

For example, an active adult weighing 150 pounds, or approximately 68 kilograms, might use that range to estimate roughly 82–109 grams per day.

Someone who is less active, has obesity, or has a medical condition may need a different approach.

In particular, people with chronic kidney disease should obtain individualized advice rather than adopting high-protein targets from fitness articles.

Our free protein calculator can help you explore a starting estimate.

Easy Ways to Include Protein

You don’t need protein shakes at every meal.

Consider familiar foods:

• Greek yogurt, eggs, or cottage cheese at breakfast.
• Chicken, fish, tofu, or lentils at lunch.
• Beans, lean meat, or tempeh at dinner.
• Yogurt, milk, or edamame as optional snacks.

Spreading protein across meals can be practical, especially if you’re strength training.

But there’s no exact amount that everyone must eat at every meal to maximize muscle growth.

What matters most is meeting your overall nutritional needs consistently.

Does Protein Speed Up Metabolism?

Your body uses energy to digest and process protein.

This is known as the thermic effect of food.

Protein generally requires more energy to process than fat and, proportionally, more than carbohydrates.

But that doesn’t mean doubling protein intake will create a dramatic increase in calorie expenditure.

Protein’s more meaningful benefits are supporting muscle, nutritional adequacy, and fullness, not turning digestion into a major fat-burning workout.

3. Increase Your Everyday Movement

Many people focus on scheduled exercise while overlooking the hours spent sitting.

Walking, household chores, gardening, and other everyday activities all contribute to energy expenditure.

This is often called non-exercise activity thermogenesis, or NEAT.

You don’t need to consciously calculate NEAT throughout the day.

Instead, look for practical opportunities to move more often.

A Simple Walking Strategy

Suppose you currently average 4,000 steps per day.

Rather than immediately aiming for 10,000, consider increasing your average to 5,000 or 5,500.

Once that feels comfortable, reassess your goal.

You might add:

• A 10-minute walk after lunch.
• A short evening walk.
• Movement breaks during long workdays.
• Walking while making phone calls.
• A trip on foot rather than by car when practical.

These changes can improve daily activity without requiring another demanding gym session.

The amount of energy you use depends on body size, walking speed, terrain, duration, and other factors.

There isn’t a reliable rule that an extra 6,000 steps always burns 300–500 calories.

Use our steps-to-calories calculator for an individualized estimate.

Remember that the result is approximate.

4. Include Cardio for Heart Health and Energy Expenditure

Resistance training and walking are valuable, but cardiovascular exercise also deserves a place in your routine.

Activities such as cycling, swimming, brisk walking, jogging, and dancing support heart and lung health.

They also contribute to energy expenditure.

The CDC recommends at least 150 minutes of moderate-intensity aerobic activity per week for adults, or 75 minutes of vigorous-intensity activity, or an equivalent combination.

For example, 30 minutes of brisk walking on five days of the week can meet the moderate-intensity target.

If you’re currently inactive, shorter sessions are a reasonable starting point.

Is HIIT Better for Metabolism After 40?

High-intensity interval training can improve cardiovascular fitness and may be time-efficient.

But it’s not necessary to improve metabolic health, and its benefits don’t make moderate exercise obsolete.

HIIT can produce a temporary increase in post-exercise energy expenditure, sometimes called the afterburn effect.

The extra calorie expenditure is generally too small and variable to justify claims that HIIT keeps your metabolism dramatically elevated for hours.

If you enjoy intervals and tolerate vigorous exercise well, they can be included.

If you have joint limitations, cardiovascular concerns, or simply prefer cycling or brisk walking, those activities remain valuable.

You don’t need to choose the most exhausting workout to get results.

5. Avoid Extreme Calorie Restriction

If weight loss has become harder, eating dramatically less might seem like the obvious solution.

But very restrictive diets can make it difficult to get enough protein, vitamins, minerals, and overall energy.

They can also contribute to fatigue and unwanted loss of fat-free tissue.

When you lose weight, your body generally requires fewer calories at its new size.

Additional physiological adaptations may also reduce energy expenditure beyond what changes in body size alone would predict.

This process is often called metabolic adaptation.

Metabolic adaptation is real, but it doesn’t mean dieting permanently damages or destroys your metabolism.

What Should You Do Instead?

If weight loss is appropriate for you, aim for an individualized, sustainable energy deficit rather than the lowest possible calorie intake.

A modest deficit may be easier to maintain and more compatible with adequate nutrition and physical activity.

There isn’t a universal calorie minimum that applies safely to every man or woman.

Your needs depend on your health, body size, activity, and circumstances.

Our guide to what happens when you eat too few calories explains why aggressive restriction can be counterproductive.

You can also use our daily calorie needs calculator to estimate your current energy requirements.

Treat the output as a starting point, not a precise measurement of your metabolism.

6. Protect Your Sleep

Sleep can influence appetite, eating behavior, glucose regulation, energy levels, and exercise recovery.

Insufficient sleep may make it harder to maintain healthy habits.

For most adults, approximately seven to nine hours of good-quality sleep is a reasonable target.

However, sleeping more doesn’t automatically increase your resting metabolic rate or cause body fat to disappear.

And the relationship between sleep, cortisol, growth hormone, and fat loss is considerably more complicated than popular metabolism advice suggests.

Practical Sleep Improvements

Consider a reasonably consistent sleep schedule, a comfortable bedroom, less caffeine close to bedtime, and a wind-down routine you can realistically maintain.

If you’re experiencing persistent insomnia, loud snoring, or excessive daytime sleepiness, seek medical advice.

Sleep apnea and other sleep disorders can interfere with sleep quality and overall health.

Our article on sleep and weight loss explains the evidence in more detail.

7. Manage Stress Without Obsessing Over Cortisol

Chronic stress can affect sleep, appetite, digestive comfort, physical activity, and eating habits.

These changes can indirectly influence body weight.

But ordinary everyday stress doesn’t automatically create a hormonal environment that forces your body to store fat around your abdomen.

Cortisol is a normal, essential hormone.

It naturally fluctuates throughout the day and rises in response to physical and psychological challenges.

Persistent cortisol excess caused by certain medical conditions is different from normal stress responses.

You don’t need to spend money on cortisol-balancing supplements or repeatedly test your cortisol levels simply because weight loss feels difficult.

Instead, focus on manageable habits such as walking, staying socially connected, making time for rest, and addressing persistent stress with appropriate support.

These steps are worthwhile for overall well-being, whether or not they change your weight.

8. Understand the Role of Menopause and Other Hormonal Changes

Hormonal transitions can affect how your body feels and how fat is distributed.

For women, perimenopause may begin during the 40s, although timing varies.

Estrogen changes can contribute to a greater tendency to store fat around the abdomen.

Sleep disturbances, hot flashes, and other symptoms may also make regular exercise and eating routines more challenging.

However, menopause doesn’t automatically mean rapid weight gain or an inability to lose fat.

Appropriate physical activity, nutrition, sleep support, and treatment of disruptive symptoms can all be helpful.

Hormone therapy may be appropriate for certain menopausal symptoms, but it isn’t prescribed simply to boost metabolism or cause weight loss.

For more specific guidance, see our article on weight loss during perimenopause.

What About Testosterone?

Low testosterone can influence muscle mass, body composition, sexual function, and other aspects of health.

But there isn’t a rule that every man over 40 needs testosterone testing.

If you have persistent symptoms that suggest a hormonal problem, discuss them with a healthcare professional.

Testosterone therapy isn’t an appropriate general-purpose weight-loss or anti-aging treatment.

9. Know When to Check Your Thyroid

Hypothyroidism is a genuine medical condition that can reduce metabolic activity and contribute to weight gain, fatigue, constipation, and cold intolerance.

But weight gain by itself doesn’t establish that your thyroid is underactive.

If you have unexplained weight changes alongside symptoms such as persistent fatigue, feeling unusually cold, constipation, or dry skin, a medical evaluation may be appropriate.

Do You Need a Full Thyroid Panel?

Not automatically.

The American Thyroid Association explains that thyroid-stimulating hormone, or TSH, is generally the best initial test for evaluating thyroid function.

Free T4 may be measured depending on the TSH result and clinical circumstances.

Free T3 and thyroid antibody tests aren’t routinely necessary for every person concerned about weight gain.

The correct testing approach depends on symptoms, medical history, and clinical findings.

If hypothyroidism is diagnosed, appropriate treatment can restore thyroid hormone levels.

But taking thyroid hormones when you don’t need them isn’t a safe weight-loss strategy.

10. Consider Creatine for Training, Not as a Metabolism Booster

Creatine monohydrate is one of the better-studied sports supplements.

When combined with resistance training, it can improve certain strength and training outcomes.

Research involving older adults also suggests potential benefits, although results differ across studies and outcomes.

That makes creatine potentially useful for some people who want to improve strength or training performance.

It does not mean creatine directly speeds up resting metabolism or burns belly fat.

Should Everyone Over 40 Take Creatine?

No.

Creatine is optional, not a requirement for maintaining muscle or managing weight.

Commonly studied maintenance amounts are around 3–5 grams of creatine monohydrate daily, but suitability depends on individual circumstances.

It can also increase scale weight through changes in muscle water content. That isn’t the same thing as gaining fat.

People with kidney disease or other relevant medical concerns should discuss supplements with their healthcare professional.

Most importantly, creatine doesn’t replace progressive resistance training, adequate food intake, or recovery.

If you’re just beginning to exercise, building a consistent routine is a more useful first priority than buying supplements.

What About Green Tea, Coffee, Spicy Foods, and Metabolism Supplements?

Several foods and beverages are marketed as metabolism boosters.

Caffeine can temporarily increase energy expenditure, while protein has a relatively high thermic effect during digestion.

But these effects don’t translate into large, predictable amounts of weight loss.

There’s no convincing evidence that cinnamon, lemon water, spicy foods, or ordinary cups of green tea can meaningfully restore a supposedly slow metabolism after 40.

Be particularly cautious with stimulant-heavy fat-burning supplements.

Some can cause side effects, interact with medications, or contain ingredients that haven’t been adequately tested for safety.

The habits with the strongest practical benefits are much less glamorous: moving regularly, strength training, eating adequately, and maintaining routines that support your health.

A Realistic Weekly Routine to Support Metabolism After 40

You don’t need to make all these changes simultaneously.

Here’s one example of a balanced week for a generally healthy adult who can comfortably perform moderate exercise.

Day	Activity	Main focus
Monday	Full-body strength training and a short walk	Muscle and strength
Tuesday	30-minute brisk walk or cycling	Cardiovascular fitness
Wednesday	30-minute brisk walk	Everyday activity
Thursday	Full-body strength training	Muscle and strength
Friday	30-minute brisk walk	Cardiovascular fitness
Saturday	60-minute walk, swim, or other moderate activity	Enjoyable movement
Sunday	Rest or gentle recreational activity	Recovery

This example provides approximately 150 minutes of moderate aerobic activity, assuming the walking sessions reach moderate intensity, plus two strength sessions.

It can be adapted to different abilities and schedules.

For someone who has been inactive for years, even 10-minute walks and a single light strength session can be an appropriate beginning.

The goal is to progress gradually.

Three Simple Food Habits to Pair With It

You can support this routine by:

1. Including a meaningful protein source in meals.
2. Eating a variety of vegetables, fruit, whole grains, and other fiber-rich foods.
3. Keeping portions appropriate for your individual energy needs.

A typical dinner might include grilled chicken or tofu, roasted potatoes, vegetables, and olive oil.

You don’t need to eliminate carbohydrates, avoid eating after 6 p.m., or follow a special metabolism diet.

How to Tell Whether Your Metabolic Health Is Improving

You don’t need to measure your resting metabolism every week.

In fact, most consumer calorie calculators estimate metabolic rate rather than directly measuring it.

Instead, focus on practical changes.

What to track	Why it can help
Strength improvements	Shows adaptation to resistance exercise
Walking distance or endurance	Reflects changes in cardiovascular fitness
Daily activity	Helps you maintain regular movement
Waist circumference	Provides context about abdominal size
Weight trends, when appropriate	Helps evaluate longer-term weight management
Energy and sleep quality	Reflects important aspects of day-to-day health

If weight management is your goal, you can use our BMR calculator to estimate resting energy requirements.

But don’t interpret a higher or lower calculator result as proof that your metabolism has improved or deteriorated.

Those estimates are heavily influenced by variables such as body weight, height, age, and the formula used.

A meaningful improvement in physical fitness may occur without a dramatic change in estimated BMR.

You don’t need to make your metabolism act 25 again. You need habits that help your body stay strong, active, and healthy at the age you are now.

When Weight Changes After 40 Deserve Medical Attention

Sometimes weight changes involve more than everyday eating and activity habits.

Discuss unexpected or persistent changes with a healthcare professional, especially if they’re accompanied by:

• Significant unexplained fatigue.
• Unusual cold intolerance.
• Persistent constipation.
• Rapid or unexplained weight gain.
• Unusual muscle weakness.
• Significant menstrual changes or disruptive menopausal symptoms.
• New symptoms after starting a medication.

These symptoms don’t necessarily mean you have a hormone or metabolic disorder.

They simply justify looking beyond generic weight-loss advice.

You may also benefit from individualized guidance if you have diabetes, heart disease, kidney disease, or another condition affecting nutrition or exercise.

The Bottom Line: How Can You Increase Metabolism After 40?

You can improve your overall energy expenditure and metabolic health after 40, but there’s no need to chase a dramatic metabolic boost.

Research suggests that metabolism adjusted for body size and composition remains relatively stable through much of adulthood.

Changes in muscle mass, daily movement, body weight, hormones, sleep, and health conditions can still affect how many calories you use and how easy weight management feels.

The most useful strategies are straightforward:

• Strength train regularly to maintain or improve muscle and strength.
• Eat adequate protein without resorting to extreme targets.
• Increase daily movement and include cardiovascular exercise.
• Avoid unnecessarily restrictive diets.
• Protect sleep and manage stress.
• Seek appropriate medical evaluation when symptoms suggest a health problem.

Creatine may support training for some people, but it isn’t a fat burner. HIIT, caffeine, and other short-term metabolic effects aren’t essential either.

If you’re also trying to lose weight, our guide to losing weight after 40 explains how to combine these habits into a sustainable plan.

The goal isn’t to force your body to burn as many calories as possible. It’s to maintain strength, stay active, support your health, and make weight management more sustainable for the years ahead.